Magnetic stacking mechanism



J1me 1953 R. 'r. CHATTERTON 2,640,605

MAGNETIC s'mcxmc MECHANISM I 50 h i B z9 i 39 34 46 INVENTOR.

35 Wrm i/M A 7'TOENEYS June 2, 1953 R. 'r. CHATTERTON 2,640,605

MAGNETIC STACKING MECHANISM Filed Dec. 30. 1947 2 Sheets-Sheet 2 INVENTOR /Z/ -A haw Patented June 2, 1953 UN IT-ED STATES OFFICE MAGNETIC STACKING MECHANISM Ro r T- Chai e t n, npin rs Fa ls, N- Y iassignor to American Can Company, New York,

N. Y.,. a corporation of NewJersey Application December 30, 1947,*SerialNo.7-94;708

.4 Claims.

The present invention relates .to .a stacking mechanism for arranging in a stackzmetal articles, such as canoroontainer end closures and has particular reference to .magnetic .devices for guiding and-arranging the articles in an orderly stack.

the automatic high speed feeding of articles especially .fiat articles 'into stacks'for subsequent refeeding, an varticle occasionally enters upon :the stack in an angular or irregular position with relation to the other articles in the stack 1 and thereby causes disorderly assembly or jams which cause interruption vof the feeding operationor:prevent.succeeding articles from-beingmroperly arranged in thestack.

The instant invention contemplates vovercoming these difliculties -by the provision of armagnetic device which provides for guiding the varticles-into'proper .position as they fall .into place on:a stack.

Anobject'of the invention is the provision in a vstacking mechanism for :flat e articles :of devices wherein the articles as they are received .for stacking are guided into a proper position prior to and during their "fall onto the stack so that they \will arrive on the .stackin-norrect relation to: the other; articles in the stack.

H Another object .is the provisionaof ,suchastacking mechanism wherein ,one or more of the-articles being stacked :are ,heldin "guided suspension over the stack forproperly receiving thearticles to he stacked-a d for lowering th articles onto the stack in orderly relation- Another object the provision Qfsnchastaoking mechanism wherein the orderly reception and. the "proper positioning :of the articles .in the stack is effected'magnetically and in such a manner as to handle the articles individually so that-scratching or otherwise marring ofcoated'or decorated surfaces maybe prevented.

.Numerousother objects and advantages of the invention will'be apparent .as .it is better understood from the following description, which, taken'in connection with the accompanying drawings, discloses .a preferred embodiment thereof.

Referring toithe drawings:

,Eigure x1 is a top plan view of a feeding and. s ae ms ch ni m embody g th instant in ven iomwi Pa ts broken away;

Ei-ghz :isa sectional view taken substantially along the line 2-72 :Fig. :.1, with parts :broken away and with parts shown iii-elevation;

' Fig." 3 is a 'view similar to'Fig. 2 and showing .amodified-formof-theinvention;and

.Eig. ,4 *is a wiring diagramof the electroma neticsystemusedin themechanism.

vAs a preferred and exemplified embodiment of :the instant invention, Figs. 1 and :2 illustrate a mechanism for feeding and stacking circular sheet metal can .endsior closures A for refeeding into ,an automatic machine ,for subsequent treatment. 'fIxhe-can iends Atare received from any suitable source o1" supply, on anendless belt conveyor VII, :the machine end of which operates over a pulley 12 mounted on'a horizontal shaft i31carried in bearings L4 formed .a frame 15 whi h c nstitute the main ;frame of the s ins m han sm- .The J' hveyo shaft 13 is rotat d by aneendlessi hain .16 which per te ver a driven sprocket H carried on the shaft, an overs d ivin pinion B oaI s ne o or shaft l f an e1 tr o :m o iz oltedzto h rame 15- The a end in a e -.c l. v r d individu ly by th o v yor intoa iihel n d chute 24 secu ed o :a bra k t 25 o the e ram -1 adja th conveyor pu l y 1.2 The l wer terminal en of th c ute is fo med wi h a v cally d spo d nd r 1 havin open t p and bottom en s- The o om :end o th r minder :re t o and is in v r c al nm n With a nonmagnet ticaL- uid -sme e o hoppe 28hliming its lo er end a flange 29 secured-in a feed -housingtl ed toth zframe h can en s A r ce ved the ch t 2 fall throughthe cylinder fil-and iorm asvertical stack B in h hopp r 28. The ends a p eferably re e zi iv duallvei om h bo om of s s ck, r su s ue t t eatm t, by a ohv nt nal f d n e ioe hich e u s e arator s rew '33 andafeed finger .34 suohas disclosed in United StatesPatent 2,172,402 issued September 12, 1939,

to v# J N r o s i -Gan T eat n Machine andFeedControl.Therefor.

In such a ;feeding device, the lowermost can end A inthe stack B rests o n a lug or shoulder 36 forme in the hou in il and on an ppositely disposed rotataiole :barrel 3110f the separator screw33. Thescrew ,barrel .is'secured to a vert a sh ur aled "in a hearin so formed in the 'housing :31. T- he shaftisrotated in any suitable manner. El e :outer periphery of the screw vbarrel 11S iiornied "with :aninclined .slot i4 1 Abovethe barreLrthe-shaitfifi.carriesa cut off or separatorknife-M.

."Hence as thezscrew barrel 31 rotates with v the shaft "38 in time with other moving parts the separator :knife i2 cuts in-between the-lowermost can end A andthe oan endynezgt above and thus temporarily supports -the=stack-above the'lower most can end. With the stack thus supported the edge of the lowermost can end on the barrel 3'! falls into the inclined slot 4| and hence rides down along this slot into the inclined position shown in Fig. 2, separated from the rest of the stack. While in this position the feed finger 34 engages behind the separated can end and sweeps it out from under the stack and carries it along the usual guide rails to any suitable place of deposit. For this purpose the feed finger 34 is mounted on the upper end of a vertical shaft 45 which is journaled in a bearing 46 formed in the housing 3!. The shaft is rotated in any suitable manner in time with the separator screw shaft 38.

The can ends A as they fall into the hopper 23 are magnetically controlled so as to insure proper guiding and positioning of the can ends on the stack. For this purpose the hopper 28 is surrounded by a pair of bar electromagnets 48 which are energized by the flow of electric current in the proper direction through a pair of coils 49 interposed between the magnets at their opposite ends as shown in Fig. 1. In other words, the bar 48 to the left (Fig. 1) is north (N) as shown and the bar 48 on the right marked S is the south pole. This sets up a magnetic field across the hopper and the ends moving therethrough. The eifect of this arrangement is the provision of two oppositely disposed horseshoe magnets. Each coil 49 sets up a magnetic field of its own and since there are two coils disposed on opposite sides of the hopper 28, there are two separate magnetic fields entering the hopper, the lines of force of one magnetic field combining with the lines of force of the other magnetic field in an extended widely distributed pattern of supporting flux. These magnets are supported on a nonmagnetic collar 5! which surrounds the lower end of the hopper and which is interposed between the bottoms of the magnets and the feed housing 3! Adjacent the hopper 28, the magnets are recessed to fit around the hopper. The inner surfaces 50 of these recesses are tapered downwardly and outwardly as shown in Fig. 2 providing a greater distance for the lines of magnetic flux of magnetic force passing between the magnets of opposite polarity as viewed from top to bottom. The space within the hopper, therefore, which is located between the pole faces of magnets may be considered as consisting of a plurality of layers or strata. These layers or magnetic lines of force, in the embodiment now being considered, have different fiux densities. Obviously since the shorter distance between the pole faces of the magnets for the conduction of the magnetic flux is at the top edges of the magnets, the greatest intensity of the field is at the top edges of the magnets surrounding the top of the hopper where the can ends enter.

Hence when a can end A is delivered by the conveyor ll into the chute 24, it slides down the chute and into the cylinder 21 and drops into the magnetic field in the hopper 28. As the first can end enters this magnetic field, the magnetic lines of force extending across the hopper act on the falling can end and bring it into a horizontal balanced position and hold it suspended temporarily at the top edges of the magnets where the intensity of the field is at its maximum.

A subsequently fed can end A as it slides down the chute 24, falls on top of the suspended can end, the suspended can end acting as a guide for the proper horizontal delivery of the subsequent can end. In this manner as each can end from the chute 24 falls into place on the stack, the other can ends settle down in the hopper 28. The magnet coils 49 preferably are of sufficient strength to maintain only a predetermined number of can ends A in suspension in the hopper 28, substantially as shown in Fig. 2. Under normal operation of the mechanism one can end A will drop from the bottom of the magnetic field and fall properly onto the top of the stack each time an entering can end is delivered from the chute 24 into the top of the field at its point of maximum intensity. The top can end of the suspended ends within the hopper always serves as a guide for an incoming can end. In this manner continuous and smooth operation of the mechanism is insured. If for any reason the can ends are fed into the hopper too rapidly or if they are not discharged from the bottom of the hopper fast enough the can ends in the hopper build up until the hopper is filled with a solid stack, the top can end always serving as a guide for an incoming can end.

When the hopper 28 is filled to capacity, the can ends on top of the stack project above the magnets 48 and engage against and operate a movable switch arm 55 disposed in a slot 55 in the chute cylinder 2'! and carried on a pivot pin 51 secured in the cylinder. This arm engages against and actuates the movable element of a normally closed electric stack or micro-switch 58 secured to the chute cylinder 27 and electrically connected to the electric motor 2|. The opening of this switch stops the motor 2| and the con veyor H and thus stops further feeding of can ends into the hopper 28 until the stack of can ends is nearly exhausted by the feeding device at the bottom of the stack. Restarting of the motor and the conveyor is controlled by a time delay device 5! (Fig. 4) which is regulated to operate in accordance with the speed of feeding of the can ends from the bottom of the stack.

As the can ends are removed from the bottom of the stack, the stack decreases in size but always a few of the uppermost can ends in the stack will remain temporarily suspended in the hopper in the region of the magnets 48 as shown in Fig. 2. In this portion of the hopper, the uppermost can end will remain in suspension at the upper edge of the magnets where the intensity of the magnetic field is at its maximum and thus this suspended can end will be ready to serve as a guide for subsequently entering can ends, when the motor 21 and conveyor I I resume operation to replenish the stack.

The time delay device 6| preferably is of the dash pot type in which a piston H (Fig. 4) contained in a cylinder 12 falls slowly against the resistance of air controlled by a vent valve 13 in the bottom of the cylinder. The valve is set to permit the piston to fall in a predetermined length of time and also allows the piston to be lifted quickly. Lifting of the piston is effected by an electric solenoid M which surrounds a core section of a rod 15 which constitutes the piston rod. Referring now to the wiring diagram in Fig. 4 it will be seen that the coils 49 of electromagnets 48 preferably are connected in parallel by wires '77, 18 to main lead wires 19, 86 of a source of electric current such as a battery or generator 8 i. It is through this connection with the source of current that the magnets are maintained in an energized condition.

The electric motor 2| controlled by themicroswitch 58 is excited through an operating circuit 3 Oiwhich includes dhe electric solenoid 11 mi the time delay device 61 which is normally energized and a time delay switch :83 wvihich ai's minimally closed. in this :circuit, :the dead 'wire i811 coii ith'e source 8| of icurrentt is connected {by :a xwire (8-4 to rone side of the-StackiSWillfihifiB. Ilhesopposite side aof thisxswitch is connected by :iamire 85 "to the motor 12:1. Ellhe motorii's-ezlso-zconnectedtbyza wire 86 tooneside for theudelay solenoid -M. mhie opposite side of this :solenoid :is {connected thy-ea. wire 88 to the :lead wire :nf .iihe source :oi ion-r rent. :Hence when the stack switch 5851's aciosed, electric current :flows through 'thisxcircuit :and operates the motor B21 EIlHiElSOiBHEXgiZBsRthH$019- noid M -.and thus :holds the :delay switch 583 closedan'd retainsttherpiston ti iinrn u'aisediposi-- tion in its zcylimier.

When :the stack of-ican endslnireachesiarheight s'ufiicient to open #the stack xswitch= 58,1thei1iircuit is broken. Thus the motor 52! (stops operating and the "delay-solenoid 1'14 isiimmedi'ately ode-energized. The .de-energization oiithesoleimiii nieleases the pistonH and ;permits it to ifalhslowly through its delay cycleiuntil Fit rre'aches the bottom or the cylinder. ns the ap-iston ifalis, zit opens'the fdelay switch s83 so that =zthBtci1iGl1it cannot l-againshe reeestablishedby the closing ofthe stack switch 53, until :the piston i ully completed its time :delay -.cycie.

During this :time delay icycie, the feeding (of the can ends from the bottom .of the stack, decreases the height of "the :rs'tack and thus permits the-stack switch '8 'to close. :However nothing happens because the :delay switch (83 :remai'ns open and thus the circuit remains broken. Upon the completion of the time delay :cycI-e'the ,delay solenoid is re-energizediand thisiquieklyraises the piston :and closes the delayrswitch $83 to arestart themotor. This re-eneiggizing oithmsolencid M isiefiected 'through aIseparateLr-estarting circuit R which includes :anormally yclosed "electric switch 9| .anda normallyiopen electric switch 92 'which'are'actuated byeng'a'gement With a projection 93 on the piston rod 15.

When the piston isin "a-rai'sed positiona's shown in Fig. 4, the zprojection 93 engages the 'normally closed switch 9! and holds .it open. However when the piston is released'and falls in itscylinder, th'eprofjectionmove's away'irom ther'sviitch and permitsthe switch to'close. When thej'piston reaches the-bottomof the cylinderfthe projection engages and closes the switch 92. Henoewith both of theseswitches "9| BZ 'clo'sied electriccurrent flows irom the wire ii t'along a connecting Wire 94, through closed switch 92, along a wire '95., through closed switch 9|, along a connecting wirevfifi, through a solenoid 91 having a movable -core 98, andalo'ng a connecting wire 99 to wire 88 and then to the lead wire 19. Electrio current flowing along this circuit R energizes the solenoid 91 and thereby closes a double switch Hill, I02 connected to the movable core 98 of the solenoid and thereby establishes two new circuits, an energizing circuit S and a holding circuit T.

The closing of the energizing circuit S permits electric current to flow from the wire 84, through the closed stack switch 58, wire 85, motor 2|, wire 86, solenoid 14, wire 81, a connecting wire I05, closed switch Ifll, a connecting wire HIE, returning to the lead wire 19. This circuit excludes the open delay switch 83 but energizes the delay solenoid 14 so as to raise the piston H and it also restarts the motor 2| to begin feeding of can ends onto the stack to replenish the stack. However as soon as the piston begins the tries, the iproieuttlin 293 (on the zpiatcii rod rides bit the sswitch rm rand permits tthis switch'zto open. lillhe openingeofzthisiswitch no effect aon lthe solenoid ilil zsince :electric rent mow flows ialong thexholdingcircuit iirom the wire me, :along 'wirecskaarconnectine wire M3,. closed switch zt'fl 2,112, momieotihg mire d239, swine 15, closed switch :91, "wine 95., rsolenoiri 8-1, Wises sail, 88, returning to the lead wire 19. Thusicurrant flowing through thisiholding circuit T keeps the solenoid 19'] energized while the :piston is rising to its upperdimit to close the delay switch '83.

When the :piston lreach'es its upper :limit of travel :an'd 'closes thesdelayswitch 83, theflowof current {through the delay isolen'oid =74 isi-transferred through the regular operating circuit Q, along the Wire 28*], "switch 83,, and wires 8,8, 179. The holding circuit IT and the energizing :circuit S :arethembrok'en. This is eiiectedby the projection 9:3 on the DiStOl'lflOd Fiiqcomingintoem gagenrent with and opening :the :switch 91 just as the piston reaches its upper limit Lof travel and closes the delay switch 83. Theopeni-ngnf thisiswitoh 9l opens-:all of thezother-circuits R, S, T excepting the operating circuit-0 and thereby returns the entire system .tDiI/S origin-almondition. The projection 1:93 :holds mhejSWl Ltfih fil open to maintain ithis zconditi'on 'until the attack, of :can ends again :reaches at height :Isuificient it!) open the stack switch :58 anditherehy repeat operationsiustexplained. v

Astxa modified :iorm of "the ainviention vEilig. 3 illustrates -a stacking mechanism which ,ris (similar to the mechanism:iexplainedihereinbcforesex- .cept that (the inner races rot "the :magnets we are parallel instead of dosing tapered as in :preferred form b shownj in iris. ;=In-:.such :a modified form of "the mechanism, a end-n es rit slides ofi the entranceichute -24 and drops through the the cylinder -21, falls into :.a imagnetic held iOf equal intensity or tthe j full depth :oi rth'el; ma nets surrounding the hopper #28. This :magneticneld extends across the hopperqat' -an rangle thereto, preferably of might angles to the travel mi lthle can sends zthrough'zthe @hopper.

:The "effect .of --.thisimagnetic .lfi-eld on {the Centering can end is :tobring the can -enddnto1athorizontal :position gzparallel with the dines @of "force of the magnetic field,-as it y enters .the :hopper unguided, and ,torslow down its \falling action, there by :permitting the can end ":to slowly ,and gently settle into a temper position :on step. zof T131138, stack TB. No :suspended -roan tends tare mecessarir to guide the *incoming ends :into :a "horizontal position, as in the preferred iiorm :of the driven-- tion.

tSuch za'modified formcof the: mechanismi-isrnde vantageous where the can ends are coated, decorated or lithographed and it is desired to prevent sliding of one end over another which might scratch or otherwise mar the surface. In this modified form of the invention the control of the replenishing of the stack, as the ends are fed from the bottom thereof, is efiected in the same manner and by similar electric circuits as explained hereinbefore for the preferred form.

The invention is not limited to a hopper which terminates in an end feed. The end feed could be omitted and the hopper used as an accumulator or counter of stacked articles for packing or deposing the stacked articles in a complete unit. Numerous other applications of the invention will occur to those who wish to utilize the same.

It is thought that the invention and many of its attendant advantages will be understood from the foregoing description, and it will be apparent that various changes may be made in the form, construction and arrangement of the parts without departing from the spirit and scope of the invention or sacrificing all of its material advantages, the form hereinbefore described being merely a preferred embodiment thereof.

I claim:

1. In a mechanism for stackingv magnetizable articles having a flat extensive area such as can ends or the like, the combination of a hopper for receiving a plurality of the articles at the top portionthereof and for accumulating them in stacked position at the bottom portion thereof, means for feeding said articles individually into said hopper, a plurality of magnets substantially surrounding said hopper, each magnet having a field of its own and the fields of all magnets continuously linking with the moving articles in said hopper thereby widely distributing the lines of force of said fields in said articles for balancing and maintaining in substantial parallelism articles entering said hopper for controlling their travel through the hopper into proper position in stacked relation.

2. In a mechanism for stacking magnetizable articles having a fiat extensive area such as can ends or the like, the combination of a hopper for receiving a plurality of the articles and for retaining them in stacked position, means for feeding said articles individually into said hopper, a pair of magnet bars located in opposition to each other and extending past said hopper on opposite sides thereof, said bars adjacent said hopper having shaped portions substantially conforming to the contour of a portion of said articles, and a pair of magnet coils disposed between adjacent ends of said magnet bars for setting up like poles at opposite ends of each of said bars for creating in said hopper and said moving articles magnetic fields having at said shaped portions of said bars widely distributed and balanced lines of force for balancing and supporting in sub-1 stantial parallelism articles entering said hopper for controlling their travel through the hopper into proper position in stacked relation. l

3. In a mechanism for stacking flat magnetiz-' able articles such as can ends or :the like, the combination of a nonmagnetic hopper for receiv'-; ing a plurality of said flat articles'and for -ac-' cumulating them in stacked position, means in:

cluding an inclined chute connecting withlthe;

top end of said hopper for. feeding said articles individually into said hopper in a near horizon--v tal position, at least a pair of magnets substantially surrounding said hopper, said magnets having portions of their inner faces shaped in substantial conformity with adjacent peripheries of said articles in the hopper, said faces adjacent said hopper tapering outwardly and downwardly from their upper edges, each of said magnets providing a magnetic field extending into said hopper and said moving articles, said fields having at the shaped portions of said magnets Widely distributed and balanced lines of force for balancing and supporting parallel articles entering said hopper, said tapered faces providing at their upper edges the maximum flux density of said fields for temporarily holding an article in suspension as a guide and temporary support for the next incoming article entering said hopper and for suspending in spaced relation other articles in said hopper for gradual lowering and positioning in stacked relation at the bottom of said hopper as incoming articles enter said hopper at its top end.

4. In a mechanism for stacking magnetizable articles having a flat extensive area such as can ends or the like, the combination of a hopper for receiving a plurality of the articles at the top portion thereof and for accumulating them in stacked position at the bottom portion thereof, means for feeding said articles individually into said hopper, a plurality of magnetizable bars substantially surrounding and conforming to the peripheries of adjacent articles in said hopper, means for magnetizing said bars to set up mutually repellant magnetic fields around said bars and entering said hopper, the lines of force of said fields combining in an extended widely distributed pattern of supporting flux to efiect continuous linking with the moving articles in said hopper in widely distributed lines of force in said articles to balance and maintain in substantial parallelism articles entering said hopper and for controlling their travel through the hopper into proper position in stacked relation.

ROBERT T. CHATTERTON.

References Cited in the file of this patent UNITED STATES PATENTS Number Name I Date 1,080,435 Gamper Dec. 2, 1913 1,304,553 Gadd May 27, 1919 2,172,402 Nordquist Sept. 12, 1939 2,336,434 Wurzbach Dec. 7, 1943 2,430,407 Nelson Nov. 4, 1947 2,474,141 Chatterton June 21, 1949 FOREIGN PATENTS Number Country Date 219,237 Germany Mar. 9, 1909 

